Solution, MAME, Mr Wadner "kill the specter upstairs and I will tell you a secret" muttered the old crone.I went through many a ball of thread and dozens of Magic Capes learning to jump the boulders the specter hurled at me. After it finished with the rocks it would lumber towards me to be cut down by my Star Sword.
Yet each time I slayed him he would return, and the Witch would cackle.
Finnaly, frustrated to the point of madness, the answer came to me.
I climbed higher, crossing the rickety floor above and snatched the key. Now I dropped into it's room – provoking the fusillade of rock. These I duely jump.
Again it rushes at me, but I use the key from upstairs to flee its enchanted chamber. It follows, lumbering, ignorant of its immenant fate. I blast it with tides of fire. When the smoke clears the Specter is gone, banished back to whichever foul realm from which it came.Later the old hag reveals to me a shortcut, greatly speeding me towards my quests end. My darling be patient I come.
Fear me Wadner for I come for you!
(On one credit too, like when I was a lad!)